The powerful V8 engines did so bearing the name LB7, and yes, they were eventually replaced by Duramax builds branded LLY.

The LB7 Duramax engine is a turbocharged, intercooled V8 that produces 300 hp and 560 lb-ft of torque. The engine made an ...

General Motors’ 6.6-liter Duramax LB7 was a state-of-the-art V8 diesel engine with four-valves-per-cylinder producing 235 to 300 hp and 500 to 520 lb-ft of torque. In addition to a turbocharger ...